GB1363016A - Telecommunication subscriber set circiut - Google Patents

Telecommunication subscriber set circiut

Info

Publication number
GB1363016A
GB1363016A GB3729272A GB3729272A GB1363016A GB 1363016 A GB1363016 A GB 1363016A GB 3729272 A GB3729272 A GB 3729272A GB 3729272 A GB3729272 A GB 3729272A GB 1363016 A GB1363016 A GB 1363016A
Authority
GB
United Kingdom
Prior art keywords
transistor
line
capacitor
circuit
aug
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB3729272A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Standard Electric Corp
Original Assignee
International Standard Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
Publication of GB1363016A publication Critical patent/GB1363016A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/26—Devices for calling a subscriber
    • H04M1/53—Generation of additional signals, e.g. additional pulses

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Interface Circuits In Exchanges (AREA)
  • Devices For Supply Of Signal Current (AREA)

Abstract

1363016 Time delay switching circuits; substation equipment INTERNATIONAL STANDARD ELECTRIC CORP 10 Aug 1972 [13 Aug 1971] 37292/72 Headings H3T and H4K A circuit for pulsing the current in a telephone line comprises a transistor T2 in series with one leg of the line, a transistor T1 connected between the base of transistor T2 and the other leg, a constant voltage device (e.g. Zener diode Z) and a resistor across the line and a timing capacitor C connected between the junction of these components and the base of transistor T1, switching means being provided to shortcircuit the voltage supply and the transistor T2. In normal operation current flows between the two legs of the line via the shunt for transistor T2 provided through a2 and to charge the capacitor C. When the switch is operated the shunt path is removed and the transistor remains off to break the current supply until the capacitor C has recharged sufficiently to allow the transistor to conduct. The switch also serves to short-circuit the microphone and receiver circuit, correct termination of the line being maintained by resistor R4.
GB3729272A 1971-08-13 1972-08-10 Telecommunication subscriber set circiut Expired GB1363016A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19712140679 DE2140679A1 (en) 1971-08-13 1971-08-13 CIRCUIT ARRANGEMENT FOR LOWERING THE CURRENT IN A COMMUNICATION LINE LOOP

Publications (1)

Publication Number Publication Date
GB1363016A true GB1363016A (en) 1974-08-14

Family

ID=5816711

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3729272A Expired GB1363016A (en) 1971-08-13 1972-08-10 Telecommunication subscriber set circiut

Country Status (2)

Country Link
DE (1) DE2140679A1 (en)
GB (1) GB1363016A (en)

Also Published As

Publication number Publication date
DE2140679A1 (en) 1973-02-22

Similar Documents

Publication Publication Date Title
US4079211A (en) Protection device for a subscriber's telephone set
GB815980A (en) Improvements relating to electrical relay circuit arrangements employing semi-conductors
US4103114A (en) Variable delay ringing detector
GB801644A (en) Improvements in or relating to relay devices employing transistors
GB1516695A (en) Switching transistor drive apparatus
GB1366984A (en) Power supply
US4360710A (en) Telephone circuit
FR2254168A1 (en) Telephone line supply device - is an active electronic device acting as resistance for direct current and high impedance for A.C.
US4086440A (en) Telephone set with loop current interruption timing control
GB1415461A (en) Switching circuit for tone-ringer or like load means
CA1063741A (en) Telephone ringing generators for subscriber loop carrier telephone systems
US4056693A (en) Voltage and current controlled converter for telephone ringing
SE8001541L (en) THREE-WIRE CIRCUIT CIRCUIT FOR PHONE DEVICE
US4025729A (en) Telephone ringing control circuits
GB1363016A (en) Telecommunication subscriber set circiut
GB1086702A (en) Electrical calling circuits
GB1205575A (en) Improvements in or relating to electronic overload protection circuits
US3748401A (en) Ring trip circuit
GB1474769A (en) Telephone trunk supervisory circuits
GB925027A (en) A protective circuit arrangement for transistors
US4234762A (en) Ring trip detector circuit
FR2366756A1 (en) Ringing signal generator for telephone networks - uses triacs instead of mechanical relays between subscriber and supply lines
GB1472442A (en) Power supply circuits
GB1475575A (en) Telephone system
CA1061490A (en) Dial impulse relay circuit

Legal Events

Date Code Title Description
PS Patent sealed
435 Patent endorsed 'licences of right' on the date specified (sect. 35/1949)
PCNP Patent ceased through non-payment of renewal fee